This is an application in response to RFA NIH-89-HL-15-P to conduct a study on the association of fasting and postprandial lipoproteins with atherosclerosis ascertained by B-mode ultrasound. Four Field Centers, a Central Lipid Laboratory, a Statistical Coordinating Center and an Administrative Core are the agencies of this multicenter application. The study is an incremental effort to research presently underway in the Atherosclerosis Risk in Communities (ARIC) Study. The source population is the community-based cohort of men and women ages 45 to 64 years sampled by the four field centers. Cases (n=300) will be drawn from ARIC participants who had B-mode ultrasound measurements of carotid arterial wall intima-media thickness indicative of atherosclerosis at the baseline visit, are free of cardiovascular disease manifestations, and not treated with lipid altering interventions. Disease-free controls (n=300) will be selected from ARIC participants with no indications of arterial wall thickening, and will be matched to cases by study center, race, age, gender, and date of examination. The criteria to define the presence or absence of atherosclerosis are supported by pilot study experience and are applied uniformly to potential cases and controls. A common and standardized protocol will be used during data collection, supported by a central coordinating center and a quality assurance program. Study participants will be administered an established and standardized fat challenge test, containing Vitamin A. Food frequency history will be taken. Blood specimens will be drawn fasting and 3.5 and 9 hours after the test meal. Various parameters of fasting and postprandial lipemia, as well as markers for intestinal and hepatic triglyceride-rich lipoproteins, will be measured. Also, factors regulating coagulation and fibrinolysis will be determined in fasting and postprandial samples. Additional study measurements on the cases and controls are available from the extensive database of the ARIC study, to serve as study outcomes potentially related to postprandial lipoproteins and to study the characteristics suspected to influence the clearance of triglyceride-rich lipoproteins.